Many drugs that are abused by man are taken by the oral route. Because most drugs abused by man are weak acids or weak bases there have been few attempts to develop models for the study of oral drug abuse patterns on animals. Our experiments have been directed toward developing models for studying oral drug abuse in animals, either by making drug solutions the only available drinking fluid, or by using conditioning methods such as reinforcing operant drug drinking with food in the food deprived rat or using the schedule induced polydipsia technique to induce drug drinking. Once stable patterns of consumption of large doses of drug are produced, as has been possible with a number of narcotic analgesics and barbiturates, both pharmacological methods (injection of antagonists for example) and behavioral methods (punishment and extinction) are used in an attempt to prevent or reverse these patterns of drug consumption. It is hoped that by studying the development, prevention and reversal of oral drug abuse patterns in animals we will be able to better understand the factors leading to development and prevention of drug abuse in man.